1. Field of the Invention
This invention relates generally to provision of power to a line card.
2. Description of the Related Art
Hardware-based line cards used in networking applications often include a variety of different Integrated Circuits (ICs), each of which receive power from one or more power lines known as power rails. As line cards increase in complexity, the number of ICs on each card is also increasing. To further complicate matters, each IC often has different power and control sequencing requirements. For example, each IC may be required to ramp up in a particular pattern with respect to other rails. Latch-up failures or excessive current draw could occur if sequencing goes awry.
Another significant design factor is the fact that these ICs often have sequencing requirements on certain control signals. For example, a first power rail might need to be stable before the second power rail. As another example, a first power rail and all clocks might need to be stable before a second power rail is activated. As another example, a reset signal may need to be asserted for a fixed amount of time after a certain power rail is stable.
Hardware engineers must often manually implement discrete circuits to meet the sequencing requirements. This is not only a time-consuming process, but results in significant inefficiencies, as the hardware engineer must redesign a new circuit whenever the components of the line card change. As a result of these inefficiencies, the current process for addressing power requirements of line cards is very expensive.
Accordingly, there is a need for a system and method that enable efficient implementation of power rail sequencing. There is a further need for an inexpensive, programmable sequencer that dynamically responds to various power rail environments.